DE3619339A1 - METHOD FOR PRODUCING A PAPER CARRIER - Google Patents

Description

The invention relates to a method for producing a paper support for photographic paper. In particular, it relates to a method of making a paper support for a photographic one Paper, which has excellent absorbency for emulsion coating and free from ripple-like irregularities in the ma sehine direction is (subsequently briefly as surface irregularities designated).

Jy photographic paper for color printing or

Black and white printing is generally done in a liquid form

Medium processed. As a result, you have paper carriers for the photographic paper from a base paper with of sufficient wet strength. Ba ryta paper, which is widely used, is a paper carrier that is generally manufactured is done by placing a wet strength base paper with a Coating composition of gelatin as a binder and dispersed therein barium sulfate, an inorganic one White pigment, coated and then dries. In the In recent years, with the increase in development speed, a paper support has mainly become made of resin-coated paper, which by coating of a base paper made on both sides with a water-resistant resin was used.

The base paper for various paper carriers is in the

generally on a Fourdrinier paper machine

manufactured in which a band is formed by that you can put a paper base on a moving one applies endless sieve cloth. The papermaking speed has increased productivity and man has made numerous efforts to despite the High speed papermaking the paper quality to maintain. A twin wire mesh type paper machine is used for the production of newsprint and printing paper in general, but has not yet been used for making photographic paper

been used.

On the other hand, improvements in the Production of photographic paper continued. For example

the coating speed has increased with the Emulsion increases and in the manufacture of photographic Paper for color printing has the previous method, in which you successively the desired number of applied, replaced by individual coating layers, that you have two or more emulsion layers at the same time or even at the same time all coatings that consist of two or more emulsion layers exist. the end For this reason, the carrier and, of course, the emulsion must meet very strict quality requirements. In particular when the entire layer is applied at the same time, a phenomenon occurs which is called "Shifting the emulsion layers" is referred to, i.e. an error in the evenness of the Coating layers made up of a special Changing the thickness of a part of the emulsion layer and this results in a mottled surface in color printing, which lowers the commercial value of the photographic paper.

Although the exact reasons for the phenomenon of Shift of the emulsion layers not yet is known, it is known that with an increase in the coating speed of the emulsion, the Shifting of the emulsion layers becomes more pronounced. Moving the emulsion layers is done in one certain measure of the surface texture of the photographic Paper, e.g. the silk finish, fine grain, matting or the shiny surface. In any The shifting of the emulsion layers occurs easier one when the coating speed is up

the emulsion increases.

The factors of a carrier which affect the shifting of the emulsion layers close Surface irregularities of the base paper used for the carrier. Moving the Emulsion layers decrease as the

Degree of surface irregularities of the base paper

decreases. For example, the phenomenon of

Shifting the emulsion layers to a certain extent Suppress mass by making the base paper

calendered to increase the bulk density

and consequently also the surface irregularities to improve. However, such treatment is not

sufficiently effective and also not

economical because it is necessary to have the · basis weight of the base paper to maintain the desired thickness of the backing. Becomes the banding speed

the paper machine increases, then this shows received base paper to an increased extent

Surface irregularities and this results an increase in the shifting of the emulsion layers.

The inventors of the present application have made thorough studies of the problem related to manufacturing a base paper, which is used for a photographic Paper carrier is suitable and which is excellent Has surface properties (small surface irregularities) and in which one has a High speed coating of emulsions can make without shifting the emulsion layers

the EmuLsionsschichten takes place, carried out and the Investigations have also been made into the manufacture of the paper on a high speed paper machine.

As a result of this thorough research did the inventors of the present application developed a method for making a paper support for use found in photography, the paper carrier being results in no shift of the emulsion layers and even if the base paper was produced on a high-speed paper machine or if you are running the emulsions at high speed applies to the carrier.

Fig. 1 is a plan view of a

Sample for measuring the delamination resistance,

Fig. 2 is a plan view of a

Device for measuring the delamination resistance, and

Fig. 3 shows an apparatus for

Measure delamination resistance with a sample attached.

The process of making a paper support for the use in photography according to the invention includes the production of a base paper for the Carrier using a Fourdrinier paper machine of the twin wire type with a lower wire mesh,

on which a paper tape is formed, and an endless one upper wire mesh, which is opposite to the lower wire mesh and with the paper tape in between is located and the upper wire mesh comes into contact with the moist tissue after the latter one Covered a distance of 5 to 12 m from the point where the paper pulp hits the lower wire mesh and adding the rate of drainage through the top wire mesh to the sum of drainage through the lower wire mesh and the upper wire mesh (hereinafter referred to as the upper drainage rate) set to 15 to 50%.

The difference between a papermaking machine and Twin wire type to a common Fourdriηier machine consists in the fact that the paper pulp is drained while it is between two wire meshes for restriction of the free surface is maintained, thereby forming a base paper having a relative uniform structure in the thickness direction. Included however, there is an even pattern of bumps and indentations, called wire mesh markings, on the upper C right) side. Because the paper pulp is drained from both sides, it is possible to shorten the wire mesh part without slowing down the paper speed to influence thereby, but the de la mi ηierung of the Ribbon occurs as shown by the drop in delamination resistance of the base paper will. Especially with a photographic paper support the processing solutions are significantly absorbed and partly in that part of the lower

Delamination resistance withheld, whereby Impurities and deterioration in appearance enter. If both positions of the upper wire mesh and the upper drainage rate according to the invention in are adjusted appropriately, it is possible to produce a base paper in which one can take advantage of the disadvantages of the

ZwiLLingsdraht paper machine suppressed and that

base paper obtained excellent surface properties and no shift of the emulsion layers

of the photographic paper that comes from such a Base paper is made.

The upper wire mesh should be arranged in such a way that it comes into contact with the damp belt after this a distance of 5 to 12 m and preferably 7 to 11 m from the point of application of the paper base has been promoted. If the distance is less than 5 m, then the paper base comes, which still has one Contains too large a proportion of water, in contact with the upper wire mesh and exercises too much there Pressure, whereby the even formation of the Band is disturbed in the thickness direction and Irregularities arise on the sheet of paper. In addition, the paper tape tends to split in two Layers split when the tape is in both directions is drained and results in a structure that is large Amounts of processing solutions during the photographic Processing absorbs, increasing the commercial value significantly is influenced, the distance exceeds 12 m, then becomes the paper base to a considerable extent drained through the lower wire mesh and the

The surface layer of the tape becomes too dense to support the to obtain the desired surface properties, whereby you then get a base paper, which does not improve with regard to the shifting of the Emu has lsion layers.

The upper drainage rate is preferably 15 to 50 X, more preferably 20 to 40%. If the upper drainage rate is below 15%, the belt will not be evenly formed in the direction of the thickness and the base paper obtained has surface properties that are similar to those of paper, which was produced with conventional four-directional machines, while if the upper drainage rate exceeds 40%, the tape tends to adopt a two-lamellar structure of an upper and a lower structure and the delamination resistance is reduced, and wire mesh markings are also present on the surface. The length of the part of the upper wire mesh with which the tape comes into contact is preferably 2.5 to 4 m.

The surface properties of the as previously described The base paper obtained is not materially thereby changed that you can both sides with a water-resistant Resin coated.

The as a carrier according to the present invention used base paper is basic. Borrowed from more natural PuLpe made. However, this can be required Base paper synthetic pulp or synthetic fibers

contain. Although the paper carrier according to the invention not particularly limited in terms of basis weight it is preferred that the base paper have a basis weight of 50 to 300 g / cm and a bulk density from 0.8 to 1.20 g / cm.

That used for the paper support according to the invention Base paper, which uses natural pulp as the main ingredient may contain wet reinforcement agent I, fixative for the reinforcing agents, electrolytes, pigments, pH regulators, dyes, fluorescent whitening agents, various polymeric compounds and other additives contain. The polymeric compounds and additives can form an aqueous slurry containing the contains natural pulp as the main ingredient, or to a sizing agent, as is the case with press gluing, Surface glue or spray glue is used, be admitted.

The paper carrier produced according to the invention can with a resin in a conventional manner such as extrusion coating, solvent coating, and like, are coated. In some cases, the applied resin can be hardened with electron beams will. A resin in film form can also be applied by dry lamination or wet lamination will. Engraving can be done by pressing the coated or laminated sheet of paper against it effect an engraving roller. In extrusion coating the engraving roller is used as a cooling roller to Coating and engraving can be carried out at the same time.

Electron beam hardening is carried out in such a way that that while it is being pressed against an engraving roller, the resin-coated sheet of paper is exposed to an electron beam L. is exposed.

The resins used for coating are, in particular, polyethylenes, although all resins which are one Have water resistance and which are not negative Have an influence on the photographic emulsions, can be used, e.g. Thermoplastic, Duroplastic, electron beam hardening resins etc ..

The resins can also contain titanium oxide, coloring agents, electrical conductivity agents, stabilizers, etc., contain.

The resin-coated paper is generally used Corona treatment suspended. If necessary, the coated paper will continue to be used with a black coating and another coating

Mistake.

The invention is explained in more detail in the examples.

EXAMPLES

(I) A mixed bag of 50 parts by weight

LBKP (bleached hard wood power pump) and 50 parts by weight LBSP (bleached Hartho Lz-SuLfitpuLpe) was in a

Hollander comminuted to a degree of grinding of 300 ml CSF (Canadian Standard Freeness). A paper base

was made by going to the obtained one

Pu Ipen slurry 0.5% by weight (on a pulp basis) of a

dimeric alkyl ketene sizing agent, 2.0 wt.% (on

Pulp basis) polyacrylamide and 0.5 wt.% (On pulp basis)

of a polyamide-epichlorhydride resin, both as

Reinforcing agents were used. The received Paper base was applied to the wire mesh on a Fourdri η i er machine operating at a speed

operated at 200 m / min. the

The position of the upper wire mesh was at a distance of 4, 5, 7, 11, 12 and 13 m respectively. The paper tape was formed with an upper drainage rate of 20% and then dried. Before completely drying

was the tape with a solution containing a

modified polyvinyl alcohol as surface sizing agent I, coated to increase surface strength and then dried. The degree of dryness and the degree of coagulation were adjusted to have a base paper with a moisture content of 8%, a basis weight of 170 g / cm and a bulk density of 1.04.

The base paper was then on one side with a Corona discharge treated and on one Melt extrusion coating apparatus having a melted (at 320 C) mixture of 50 wt.% of a high-density polyethylene (density 0.96, melt index 7) and 50 parts by weight of a low-density polyethylene (Density 0.92, melting index 5) in a thickness of 3 0. around coated. The opposite side of the base paper

a corona treatment was suspended and low density with a molten (at 32O ⁰ C) polyethylene containing 9% Anata-titania-coated in a thickness of (the u tion rsp L i before ni CHT-pi gment e d

Polyethylene had a density of 0.92 and one

Melt index of 5). The resin-coated surfaces

were matted by means of a chill roll with a central roughness of 1 μm.

The resin-coated backing was coated with emulsions for

color printing by the simultaneous method Applying the entire coating coated. the

Coating speed was varied until the maximum tolerable displacement of the emulsion layers

was observed.

The test results are shown in Table 1.

TABLE 1

sample 1 Speed
age
of the wire
tissue
(m / min) position
of
upper
Wire mesh
bes (m) upper ent
watering
rate (%) valuation
the waiter-
f area
regularly-
speed Miscellaneous
exercise of
Emulsions
layers
(m / min) Delami
renational
persistent
age
Cg) COMPARATIVE EXAMPLE 1 200 4th 20th 4th 130 64 example 2 Il 5 Il 3 180 90 example 3 Il 7th It 2 200 t 105 example 4th Il 11th Il 2 200 t 110 example 2 Il 12th Il 3 180 110 Comparative example Il 13th Il 4th 120 112

ANNOTATION:

The maximum coating speed in the Coater was 200 m / min. That's why 200 "t" means that at a coating speed from 200 m / min essentially no displacement was established.

The surface imperfection was due to visual Investigation of the groove-shaped irregularities in Machine direction evaluated and according to a numerical evaluation system expressed. One lower rating means higher smoothness.

(II) Wet belts were made using the same paper base used in Examples 1 through 4 and in Comparative Examples 1 and 2 were used, with different drainage rates of 14, 15, 20, 40, 50 and 53%, with the position of the top wire mesh at a distance of 9 m has been set. As described in the above examples and comparative examples, each of the tapes with the modified polyvinyl alcohol

coated and then to a base paper with 8.2%

2 moisture content, a basis weight of 170 g / m

and dried to a bulk density of 0.92.

In the same manner as in the above Examples and Comparative Examples, each of the base papers coated with a resin and then with emulsions for color printing by the simultaneous method

Applying all of the coatings overcoated The coated photographic paper was applied to the maximum coating speed until receipt a maximum tolerable shift in the Emulsion layers checked.

The test results are shown in Table 2.

TABLE 2

sample 3 Speed
age
of the wire
tissue
(m / min) position
of
upper
Wire mesh
bes (m) upper ent
watering
rate (%) valuation
the waiter-
ΐ surface
regularly-
speed Miscellaneous
exercise of
Emulsions
layers
(m / min) DeLami
renational
persistent
age
(G) COMPARATIVE EXAMPLE 5 200 9 53 4th 140 55 Example 6th 1 I. I I 50 3 180 75 Example 3 I I 11th 40 2 200 f 103 Example 7th I t I I 20th 2 200 f 115 Example 4th Il I I 15th 3 170 115 Comparative example I I I I 14th 4th 130 115

CO CO CO CD

The delamination resistance in Tables 1 and 2 was checked in the following manner. The lower tolerable limit is 70 g.

As shown in Fig. 1, a sample (1) of the double-sided resin-coated paper from the back to the middle layer using a twin blade cutter cut of the parallel type, the blades 7 mm stand apart and making parallel cuts

(2) at a distance of 7 mm and with a length of

9 cm received. Part of this cut was made

peeled off. Part of the peeled back part (3) was through the opening (6) with a size of 1 × 10 cm on the holding plate (4) of the test device as they are is shown in Fig. 2, to a water receiver (8) by means of a clamp (7) and a pulling piece (9), as shown in Fig. 3, connected. Water became given in certain quantities in the container (8) until delamination of the test piece has taken place. Dan Total weight, expressed in grams, water and container

is called delamination resistance.

The results in Tables 1 and 2 show that that a obtained by the inventive method photographic paper carrier low surface irregularities

has and practically no shift in the Emulsion layers takes place, even if you have the

High speed emulsions according to the method the simultaneous application of the entire coating layer brings up. As a result, one can greatly improve the productivity in the emulsion coating step.

Claims (5)

PATENT CLAIMS Process for the production of a paper support for one photographic paper on one Fourdrinier paper machine of the twin wire mesh type with a lower wire mesh on which a paper band is formed and an endless upper wire mesh, which is opposite the lower wire mesh and between which the paper tape is located, characterized in that the upper wire mesh is in contact with the paper tape is brought after the latter a distance of 5 to 12 m from the point of application of the paper base has moved onto the lower wire mesh and the rate of drainage through the top wire mesh to the sum of the drainage through the lower Wire mesh and the top wire mesh on 15 bis 50% is set. 2. Process for the production of a paper carrier for Photographic paper according to claim 1, characterized marked that the lower wire mesh comes into contact with the paper tape, after the latter a distance of 7 to 11 m from the point at which the paper base is on the lower wire mesh has moved. 3. Process for the production of a paper carrier for a photographic paper according to claim 1, characterized in that the drainage rate is 20 to 40%. 4. Process for the production of a paper support for a photographic paper according to claim 1, characterized in that the Length of the part of the upper wire mesh with which the paper tape comes into contact, 2.5 to 4 m " amounts to. 5. Method of making a paper carrier according to claim 1, further characterized characterized in that both surfaces of the paper fabric are coated with polyethylene are. INSPECTED